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Study of the Protective Capacity of Cements Regarding Corrosion of Reinforcements under Joint Action of CO2 and Chloride Ions

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Journal of Civil Engineering and Architecture 2015年第9期9卷 1017-1024页

作者： Eliana Cristina Barreto Monteiro victor correia de oliveira pereira department of Civil Engineering University of Pernambuco Recife 50720-001 Brazil department of Civil Engineering Catholic University of Pernambuco Recife 50050 900 Brazil

To examine the protection against reinforcement corrosion due to the combined action of CO2 and chlorides, experimental results of the evaluation of a study with three types of cement are presented. The study was performed observing the behavior of reinforcements which were put in samples submitted to accelerated carbonatation tests and accelerated tests under the effect of chlorides. For the evaluation, intensity corrosion measurements were used using the Pr （polarization resistance） technique, employing these measures as a deterioration indicator. Three types of cement available in the national market were used. The obtained results enabled the classification of the used cements, comparing their profile behaviors in the conditions of the proposed tests.

关键词： Carbonation chlorides corrosion reinforced concrete polarization resistance.

ENSO impacts on litter stocks and water holding capacity in secondary forests in eastern Amazonia

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Journal of Forestry Research 2024年第1期35卷 83-89页

作者： Julia Isabella de Matos Rodrigues Walmer Bruno Rocha Martins victor pereira de oliveira Myriam Suelen da Silva Wanzerley Hélio Brito dos Santos Júnior Francisco de Assis oliveira Graduate Program in Forestry Sciences Av.Presidente Tancredo Neves2501BelémPará66077-530Brazil Federal Rural University of Amazonia Av.Presidente Tancredo Neves2501BelémPará66077-530Brazil Federal Rural University of Amazonia Tv.Pau-AmareloCapitão PoçoPará68650-000Brazil National Institute of Amazonia Research Av.Constelação Cruzeiro do SulManausAmazonas 69060-062Brazil

Among the impacts of climate change,there is the intensification of phenomena such as the El Niño South-ern Oscillation(ENSO)responsible for El Niño and La Niñ***,understanding their effects on the functional pro-cesses of forests is ***,this study evaluated the effects of ENSO on litter stock and water holding capac-ity(WHC)in a successional forest in eastern *** occurred in periods with the most rainfall in El Niño(2019)and least in La Niña(2021)*** permanent plots were used to sample *** effects were evident for WHC,higher during El Niñ***,this influence was not clear for litter,as only in the rainy season effects were *** was a positive correlation of WHC with precipitation and humidity,while litter stocks were negatively correlated with temperature and wind *** the subject of this study requires long-term assessments,preliminary results suggests that,depending on the intensity of ENSO,forest functional processes can be strongly impacted and *** conclusion reinforces warnings by the scientific community about the impacts of climate change on the maintenance of litter stocks,decomposition and,consequently,the biogeochemical cycle and essential ecosystem services for the maintenance of Amazonia *** need to develop long-term research to understand the effects of climatic change on litter stocks and water holding capacity is highlighted,especially in Amazonia.

关键词： Seasonality Climate change Succession ecosystem Biogeochemical cycle Amazonia biodiversity

Participatory Early Warning Systems: Youth, Citizen Science,and Intergenerational Dialogues on Disaster Risk Reduction in Brazil

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International Journal of Disaster Risk Science 2017年第4期8卷 390-401页

作者： victor Marchezini Rachel Trajber Dbora Olivato Viviana Aguilar Muoz Fernando de oliveira pereira Andra Eliza oliveira Luz Cemaden–National Early Warning and Monitoring Center of Natural Disasters Distrito de Eugênio de MeloSo JosDos Campos

Building national people-centered early warning systems(EWS) is strongly recommended by the United Nations International Strategy for Disaster Reduction(UNISDR). Most of the scientific literature is critical of the conventional view of EWS as a linear model with a topdown approach, in which technological features are given more attention than human factors. It is argued that EWS should be people-centered, and used for risk prevention,with an emphasis on resilience, rather than only being triggered when a hazard occurs. However, both the UNISDR and the literature fail to say how a people-centered EWS should be built, and what steps are needed to put EWS into effect. This article examines the obstacles and measures required to promote people-centered EWS,with a focus on the situation in Brazil. After assessing the institutional vulnerability of EWS, we analyze some measures that can be taken to reduce institutional vulnerability,based on experiences with a participatory citizen science educational project that involved high school *** guidelines are developed for adopting a bottom-up approach towards achieving the four elements of EWS—risk knowledge, monitoring, communication of warnings,and response capability—with the help of school curricula.

关键词： Brazil Capacity building Citizen science Disaster risk reduction Early warning systems Resilient schools

Molecule-based kinetic modeling by Monte Carlo methods for heavy petroleum conversion

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Science China Chemistry 2013年第11期56卷 1608-1622页

作者： de oliveira Luís pereira VERSTRAETE Jan J. KOLB Max IFP Energies nouvelles Rond-point de l'échangeur de Solaize-BP 369360 SolaizeFrance Laboratoire de Chimie cole Normale Supérieure69364 Lyon Cedex 07France

A methodology for kinetic modeling of conversion processes is *** proposed approach allows to overcome the lack of molecular detail of the petroleum fractions and to simulate the reactions of the process by means of a two-step *** the first step,a synthetic mixture of molecules representing the feedstock is generated via a molecular reconstruction method,termed SR-REM molecular *** the second step,a kinetic Monte Carlo method,termed stochastic simulation algorithm(SSA),is used to simulate the effect of the conversion reactions on the mixture of *** resulting methodology is applied to the Athabasca vacuum residue *** adequate molecular representation of the vacuum residue is obtained using the SR-REM *** reaction simulations present a good agreement with the laboratory data for Athabasca vacuum residue *** addition,the proposed methodology provides the molecular detail of the vacuum residue conversion throughout the reactions simulations.

关键词： Monte-Carlo molecular reconstruction kinetic modeling stochastic simulation algorithm vacuum residue hydrocracking

Femtosecond laser-assisted deep anterior lamellar keratoplasty in phototherapeutic keratectomy versus the big-bubble technique in keratoconus

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International Journal of Ophthalmology(English edition) 2018年第5期11卷 807-812页

作者： Jarbas pereira de Macedo Lauro Augusto de oliveira Flavio Hirai Luciene Barbosa de Sousa department of Ophthalmology and Visual Sciences Escola Paulista de MedicinaUniversidade Federal de S?o Paulo

AIM：To compare the functional and anatomic results of femtosecond laser（FSL）-assisted deep anterior lamellar keratoplasty（DALK） associated with phototherapeutic keratectomy（PTK） and FSL-assisted DALK performed using the big-bubble technique in ***：During the first phase of the study,an electron microscopy histopathology pilot study was conducted that included four unsuitable donor corneas divided into two groups：in FSL group,FSL lamellar cuts were performed on two corneas and in FSL＋PTK group,PTK was performed at the stromal beds of two corneas after FSL lamellar cuts were *** the second phase of the study,a randomized clinical trial was conducted that included two treatment groups of patients with keratoconus：group 1（n=14 eyes） underwent FSL-assisted DALK associated with PTK and group 2（n=12 eyes） underwent FSL-assisted DALK associated with the bigbubble *** main outcome measures were the postoperative visual acuity（VA） and optical coherence tomography（OCT） measurements,confocal microscopic findings,and contrast ***：In the pilot study,histopathology showed a more regular stromal bed in the FSL＋PTK *** the clinical trial,group 1 had significantly worse best spectaclecorrected VA and contrast sensitivity（P〈0.05 for both comparisons）.The residual stromal bed measured by OCT was significantly（P〈0.05） thicker in group *** microscopy detected opacities only at the donor-receptor interface in group ***：Patients with keratoconus treated with FSL-assisted DALK performed using the big-bubble technique fare better than treated with FSL-assisted DALK associated with PTK.

关键词： deep anterior lamellar keratoplasty phototherapeutic keratectomy big-bubble technique keratoconus

Ecophysiology and multivariate analysis for production of Tachigali vulgaris in Brazil:Influence of rainfall seasonality and fertilization

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Journal of Forestry Research 2023年第5期34卷 1289-1305页

作者： Pedro Henrique oliveira Simoes Candido Ferreira de oliveira Neto Manoel Tavares de Paula Dênmora Gomes de Araújo Rodrigo Silva do Vale Joao Olegário pereira de Carvalho Universidade Federal de Mato Grosso Campus Universitario de SinopSinop 78550728Mato GrossoBrazil Universidade Federal Rural da Amazonia Campus BelemBelem 66077830ParaBrazil Universidade do Estado do Para Centro de Ciencias Naturais e TecnologiaBelem 66095015ParaBrazil Universidade Federal Rural da Amazonia Campus Capitao-PocoCapitao Poco 68650000ParaBrazil

Studies on fertilization management of species native to the Amazon for energy plantations contribute to the diversity of species use and reduce biological risk due to the excessive use of clones or hybrids of *** study evaluates the effect of precipitation seasonality and phosphorus and potassium fertilization on gas exchange in a Tachigali vulgaris *** levels of P(zero,65.2,130.4 kg ha^(-1))and three of K(zero,100.0,200.0 kg ha^(-1))were applied in a 3×3 factorial randomized block *** exchange measurements were conducted in April and November *** low rainfall,high irradiance period,photo synthetic rates were up to four times higher than in the high rainfall period,reaching 20.3μmol m^(-2)s^(-1)in the treatment with 130.4 g kg^(-1)of P and 100.0 g kg^(-1)of *** analysis and principal component analysis reduced the initial eight gas exchange variables to two and three principal components in periods of high and low rainfall,*** multivariate method used in this study readily identified variations in the variables as a function of rainfall,with high reliability in explaining the data set.

关键词： Photosynthesis rate Stomatal conductance Principal component analysis Factor analysis Tachigali vulgaris

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Effect of silymarin on biochemical indicators in patients with liver disease: systematic review with meta-analysis

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World Journal of Gastroenterology 2017年第27期23卷 5004-5017页

作者： Camila Ribeiro de Avelar Emile Miranda pereira Priscila Ribas de Farias Costa Rosangela Passos de Jesus Lucivalda pereira Magalhaes de oliveira Postgraduation Program Federal University of Bahia departament of Science Nutrition Federal University of Bahia

To evaluate the effect of silymarin on the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma glutamyl transpeptidase (γGT) in patients with liver diseases. METHODSA systematic review with meta-analysis of ramdomized and controlled clinical trials was performed, evaluating the effects of sylimarin in patients with hepatic diseases, published by January 31, 2016. Clinical trials were sought on the basis of The Cochrane Central Register of Controlled Trials in the Cochrane Library, PubMed/Medline, Scopus, Web of Science, Lilacs and Clinical Trials. The trials with adult and elderly patients of both sexes, with Liver Diseases who took oral silymarin supplementation, as extract or isolated, as well as Silymarin combined with other nutrients, were included. The trials should provide information about the intervention, such as dosages and detailing of the product used, besides the mean and standard deviation of serum levels of ALT, AST and γGT of the baseline and at the end of the intervention. RESULTSAn amount of 10904 publications were identified. From those, only 17 were included in the systematic review and 6 in the meta-analysis, according to the used selection criteria. In this meta-analysis, the results indicated a reduction of 0.26 IU/mL (95%CI: -0.46-0.07, P = 0.007) at the level of ALT and 0.53 IU/mL (95%CI: -0.74-0.32, P = 0.000) at the serum levels of AST after using the silymarin, both, statistically significant, but with no clinical relevance. There was no significant change in the γGT levels. Subgroup analyzes were also performed for the biochemical markers in relation to the type of intervention, whether silymarin isolated or associated with other nutrients and the time of intervention (whether ≥ 6 mo or degree of heterogeneity and low methodological quality in the carried out analysis. CONCLUSIONSilymarin minimally reduced, but w

关键词： Systematic review Liver diseases Milk thistle Silymarin Meta-analysis

A review on the synergism between corrosion and fatigue of magnesium alloys:Mechanisms and processes on the micro-scale

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Journal of Magnesium and Alloys 2024年第8期12卷 3062-3093页

作者： Mara Cristina Lopes de oliveira Rejane Maria pereira da Silva Ricardo M.Souto Renato Altobelli Antunes Federal University of the ABC Center for EngineeringModeling and Applied Social SciencesAv.Dos Estados500109280-560 Santo AndréSPBrazil department of Chemistry-PPGQ State University of PiauíUESPICampus Poeta Torquato NetoPirajáTeresina 64002-150 PIBrazil Institute of Material Science and Nanotechnology University of La LagunaP.O.Box 45638200 La LagunaTenerifeSpain

Understanding the interaction between cyclic stresses and corrosion of magnesium(Mg)and its alloys is increasingly in demand due to the continuous expansion of structural applications of these *** review is dedicated to exploring the corrosion-fatigue mechanisms of these materials,with an emphasis on microscale processes,and the possibility of expanding current knowledge on this topic using scanning electrochemical *** interaction between fatigue and corrosion of Mg alloys is analyzed by considering the microstructural aspects(grain size,precipitates,deformation twins),as well as the formation of ***,in the case of coated alloys,the role of coating defects in these phenomena is also *** this context,the feasibility of using scanning electrochemical microscopy(SECM),scanning vibrating electrode technique(SVET),scanning ion-selective electrode technique(SIET),localized electrochemical impedance spectroscopy(LEIS)and scanning Kelvin probe(SKP)methods to study the corrosion-fatigue interaction of Mg alloys is examined.A comprehensive review of the current literature in this field is presented,and the opportunities and limitations of consolidating the use of these techniques to study the microscale processes involved in Mg corrosion-fatigue are discussed.

关键词： Magnesium alloys Localized corrosion and protection Fatigue Scanning electrochemical microscopy Scanning vibrating electrode technique Scanning ion-selective electrode technique Scanning Kelvin probe Chemical imaging

Investigating local corrosion processes of magnesium alloys with scanning probe electrochemical techniques: A review

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Journal of Magnesium and Alloys 2022年第11期10卷 2997-3030页

作者： Mara Cristina Lopes de oliveira Rejane Maria pereira da Silva Ricardo M.Souto Renato Altobelli Antunes Federal University of ABC Center for EngineeringModeling and Applied Social SciencesAv.Dos Estados500109210-580Santo AndréSP Brazil Instituto de Pesquisas Energéticas e Nucleares IPEN/CNENAv.Prof.Lineu Prestes2242São PauloBrazil Institute of Material Science and Nanotechnology University of La LagunaP.O.Box 456La LagunaTenerife 38200Spain

The study of corrosion of magnesium and its alloys has emerged a hot topic in the applications of lightweight structural materials. The inherently high electrochemical activity of bare magnesium surfaces still lacks a convincing mechanism to describe the observed experimental characteristics, and it has prompted the development of various types of protective coatings with the aim of slowing metal dissolution. In recent years, new instruments and techniques have been developed to study with spatial resolution the local corrosion processes that occur in metallic materials in general, and for magnesium and its alloys in particular, both for bare surfaces and coated. Scanning microelectrochemical techniques, such as local electrochemical impedance spectroscopy(LEIS), scanning electrochemical microscopy(SECM), scanning vibrating electrode technique(SVET), scanning ion-selective electrode technique(SIET) and scanning Kelvin probe(SKP) can provide information about the local electrochemical activity of metallic surfaces. In the present work, the applications of these techniques in corrosion studies of magnesium and its alloys are reviewed. Assessment of corrosion mechanisms, barrier properties of conventional coatings and active corrosion behavior of self-healing coatings are examined. Limitations and future developments in this area are discussed.

关键词： Magnesium alloys LEIS SECM SVET SIET SKP